The present invention pertains to a multi-platen press for pressing chipboards and the like without spacer strips, with a stationary and a movable press table, between which the individual press stages are mounted.
There has been a requirement for a long time to produce chipboards or the like without spacer strips, which are located between the individual press stages in order to maintain the exact thickness of the plates to be pressed. In spite of extensive trials, however, pressing without spacer strips presents still extraordinary difficulties. The tolerances in the thicknesses of the pressed plates were such that it was only possible to work with substantial additional tolerances and these had to be equalized to the correct thickness by grinding down after the pressing. It needs no special explanation that this leads to a great amount of waste of material. Apart from that, this type of pressing is rather expensive. Hence, generally, spacer strips are used in order to ensure the correct dimensioning of the pressed plates.
On the other hand, however, the use of spacer strips brings about certain difficulties during the pressing. Thus, for example, for different thicknesses of the plates to be pressed, the spacer strips must always be exchanged. A particular disadvantage is that during the closure of the press, chips may be trapped between the stage plates and the spacer strips so that variations in the thickness may occur also in this case. It is therefore necessary to provide special equipment, whereby such obstacles may be removed just before the press is closed. These constructions are rather expensive.